Messages in this thread | | | Subject | Re: [patch] make pit clocksource continuous | From | Thomas Gleixner <> | Date | Sun, 13 May 2007 16:54:53 +0200 |
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On Sun, 2007-05-13 at 13:04 +0400, Stas Sergeev wrote: > Hello. > > Thomas Gleixner wrote: > > The PIT can only be used as a clock source, when it is in periodic mode, > > but it is never continuous. If we miss one PIT interrupt the time > > keeping is hosed.
> OK, thank you and Daniel for the explanations > about the flag, but now to the problem. > Before hrtimer_switch_to_hres() is called, > the check for timekeeping_is_continuous() is > performed in tick_ckeck_oneshot_change(), and > that check fails (by adding a flag I compel it > to succeed).
It succeeds, but it does not work correctly, because your time keeping is unreliable.
> With that check failing, > hrtimer_switch_to_hres() is never called, and > the hrtimers do not work. That's why I posted > that patch, but what would be the right way > of getting the hrtimers to work? > /proc/timer_list lists only the pit timesource. > If I enable lapic then it is also listed, yet > it doesn't help at all.
You need either pm_timer or hpet in order to switch to highres / dynticks. Are those enabled in the kernel config ?
tglx
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